Wheel cover

ABSTRACT

The present invention relates to a wheel cover in use for motor vehicles. The wheel cover includes a circular main body, a plurality of holding claws extending from a rear surface of the main body, and a resilient ring to be mounted on the holding claws so as to urge radially outwardly the holding claws. On the rear surface of the main body at positions between the neighboring holding claws are arranged support members each having a groove for receiving the resilient ring. The groove is defined by a bottom surface and a pair of protrusions aligning along the radial direction of the main body. The radial movement of the ring mounted on the holding claws can be regulated by the pair of protrusions so that the expansion of the ring is restricted, resulting in that the holding claws is prevented from expanding radially outwardly, and the ring is prevented from disengaging from the holding claws.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an automobile wheel cover, and moreparticularly, to a wheel cover, wherein, when the wheel cover is fixedto a wheel, a plurality of holding claws protruding from the rearsurface of the wheel cover are urged toward a rim of a wheel by means ofa resilient ring in the radially outward direction.

2. Prior Art

Conventional wheel covers have a variety of constructions: for example,a wheel cover as shown in FIGS. 1 and 2 is described in Japanese firstpatent Publication No. 67602/1981. Referring to FIGS. 1 and 2, aplurality of holding claws 22 are formed on the rear surface of thewheel cover main body 21, a groove 22a is formed on the radially insidesurface of each holding claw 22, and a base portion 23b of anarch-shaped protrusion 23a of the wire ring 23 is pressed to contactwith stoppers 24 which is formed at both sides of the holding claw 22 soas to protrude from the rear surface of the wheel cover main body,whereby the radially outwardly spreading force of the wire ring 23 isreceived by means of the stoppers 24. When holding claws 22 are radiallyinwardly bent during a mounting operation of the wheel cover onto thewheel, the protrusion 23a of the wire ring 23 is also bent, therebyapplying resilient force of the wire ring 23 as well as the resilientforce of the holding claw, thus a great resilient force is applied tothe holding claw 22 even by a slight degree of bending of the holdingclaw 22. In the construction described above, when fitting the wheelcover to the wheel, some holding claws 22 of the wheel cover 21 arefirst bent toward the central portion of the wheel cover so as to abuton the wheel rim, then the rest of the holding claws are gradually benttoward the central portion so as to fit the entire wheel cover to thewheel rim, whereby holding claws 22 are pressed to contact with thewheel rim with the aid of the foregoing resilient force in order to fitthe wheel cover 21 to the wheel.

For another construction of a conventional wheel cover as shown in FIG.3 is described in Japanese first Patent Publication No. 67601/1981. Thewheel cover in FIG. 3 has basically the same construction as the onedescribed above; however its construction of the wire ring is altered,i.e., as shown in FIG. 3, a ratio of a radial dimension R from thecenter of the wire ring 27 to a protrusion 27a and a radial dimension rfrom the foregoing center to a base portion 27b of the protrusion 27a,is properly set, whereby, as shown by a dotted line in the drawing, whenthe protrusion 27a is bent inwardly toward the central portion with theaid of the holding claw, the base portion 27b is also bent in the samedirection together with the holding claw. Thus, the protrusion 27a ofthe wire ring 27 is provided with a large stroke so as to resist theresilient force of the wire ring and the foregoing holding claw by meansof utilizing a large vacant space located inside the wheel rim.

According to the constructions described above, however, the wire ringis provided with a multiplicity of protrusions, whereby the number ofshaping procedures for shaping the protrusions becomes large, increasingthe production cost to a great extent. When the number of protrusions ofthe wire ring is reduced in order to lower the cost for the wire ring,the number of holding claws corresponding to the protrusions is alsoreduced, resulting in the increased holding force applied on the wheelrim exerted by each holding claw, whereby the bending degree of eachholding claw is accordingly increased such that it is difficult for thewheel cover to be fitted in the wheel. Furthermore, there is provided noregulating means for bending the wire ring in the radially insideportion of the wire ring, causing the wire ring to freely bend, wherebythe wire ring is apt to be removed from the holding claw.

SUMMARY OF THE INVENTION

The object of the present invention is, therefore, to solve thedisadvantages described above, and more particularly, to provide a wheelcover which can be produced at a lower cost, which is easily fitted tothe wheel, and once fitted which is firmly secured with the aid of theresilience force of the holding claw as well as the resilient ring, andbeing free from the worry of being removed.

To achieve the foregoing object, according to the present invention,there is employed a construction wherein the resilient ring is circularand received by support members each having a groove defined by a pairof protrusions for regulating the radial movement of the resilient ring.Specifically, the support member for radially movably supporting theresilient ring is formed between the adjacent holding claws arranged onthe rear surface of the wheel cover main body. A pair of protrusions forregulating the radial movement of foregoing resilient ring are formed,at radially inside and outside portions of the surface of the supportmember confronting the wheel. Further, the radially inside end surfaceof the protrusion positioned radially outside portion is so arranged asto be located radially outside the radially inside end surface of thegroove of the holding claw.

In the construction described above, when fitting the wheel cover to awheel, some of the holding claws of the wheel cover are bent in thedirection of the central portion of the main body, thus causing theresilient ring to bend in the same direction together with the holdingcraws. The resilient ring is deformed by the bending action, however,the radial movement of the resilient ring is restricted by theprotrusions of the support members, whereby the resilient ring itselfdoes not expand radially outwardly and, at the same time, the holdingclaws of the other portion of the wheel cover do not expand radiallyoutwardly. Then, the wheel cover is fitted to the wheel cover with therest of the holding claws bent followed by foregoing some holding claws.

BRIEF DESCRIPTION OF THE DRAWING

The above objects and features of the present invention will becomeapparent from the following description taken in conjunction with thepreferred embodiments thereof, with reference to the accompanyingdrawings, in which:

FIGS. 1 and 2 are a rear view and a cross sectional view of a mainportion of a conventional wheel cover, respectively, as previouslydescribed;

FIG. 3 is a plan view showing a wire ring of another conventional wheelcover, as previously described;

FIGS. 4 and 5 are a perspective view and a rear view, respectively,showing a rear main portion of a wheel cover of Embodiment 1 accordingto the present invention;

FIGS. 6 and 7 are a cross sectional view taken on line VI--VI and lineVII--VII of FIG. 5, respectively;

FIG. 8 is a top plan view of a holding claw according to Embodiment 1;

FIG. 9 is a cross sectional view taken on line IX--IX of FIG. 5;

FIGS. 10 and 11 are cross sectional views of the main portion of thewheel cover attached to a wheel;

FIGS. 12 and 13 are explanatory views showing the movement of the metalmold when molding the holding claws of the wheel cover according toEmbodiment 1;

FIG. 14 is a perspective view of a holding claw of a wheel coveraccording to Embodiment 2 of the present invention;

FIG. 5 is a schematic rear view of a wheel cover having the holding clawas shown in FIG. 14;

FIG. 16 is a schematic rear view of the wheel cover;

FIG. 17 is a vertical sectional view of the holding claw as shown inFIG. 14;

FIG. 18 is a top plan view of the holding claw as shown in FIGS. 14-17;

FIG. 19 is an explanatory view according to Embodiment 2 showing themovement of the metal mold when molding the holding claw;

FIG. 20 is a sectional view of the main portion of the wheel coveraccording to Embodiment 2 showing the engagement of the wheel cover andwheel;

FIG. 21 is an enlarged explanatory side view of the holding claw asshown in FIG. 14;

FIGS. 22A, 22B and 22C are, respectively, explanatory views showing theprocess of fitting the holding claw to the wheel;

FIGS. 23A, 23B, 23C and 23D are, respectively, graphs showing therelationships of the values of S, θ, 1/tan θ, and F with respect to thebending degree of the holding claw;

FIGS. 24 and 25 are perspective explanatory views showing the holdingclaw as shown in FIG. 14;

FIG. 26 is a perspective view of a holding claw of a wheel coveraccording to Embodiment 3 of the present invention;

FIG. 27 is a schematic rear view of a wheel cover as shown in FIG. 26;

FIG. 28 is an enlarged top plan view of the holding claw and supportmembers as shown in FIG. 27;

FIG. 29 is a vertical sectional view according to Embodiment 3, showingthe configuration wherein the holding claw engaged with a wire ring anda rim of the wheel are being pressed together;

FIG. 30 is a front view of the holding claw as shown in FIG. 26;

FIG. 31 is an explanatory view according to Embodiment 3, showing themovement of the metal mold when molding the holding claw;

FIG. 32 is a top plan view similar to FIG. 28, showing a modification ofEmbodiment 3;

FIG. 33 is an explanatory view showing the relationship between theholding claw and wheel rim of the foregoing wheel cover, as shown inFIG. 10, therein serially presenting: an explanatory view (a) of thearrangement of the wheel and the holding claw; a moment diagram (b) interms of the component force Ps, in the axial direction of the legportion, acting on the leg portion of the holding claw; a moment diagram(c) in terms of the radial component force Pr; and a moment diagram (d)showing the sum of both the foregoing moment diagrams;

FIG. 34 is an explanatory view showing the relationship between theconfiguration of the head portion of the holding claw and wheel rim, asshown in FIG. 10;

FIG. 35 is a rear view showing a part of a wheel cover according toEmbodiment 4 of the present invention;

FIG. 36 is a sectional view of the essential part of the wheel coveraccording to Embodiment 4 which is mounted on a wheel; and

FIGS. 37-39 are enlarged sectional views of the leg portion of theholding claw according to modifications of Embodiment 4, respectively.

DETAILED DESCRIPTION OF THE INVENTION Embodiment 1

FIGS. 4-11 show Embodiment 1 according to the present invention.

Referring to FIGS. 4 and 5, a wheel cover 1 according to the presentinvention is generally provided with a plurality of holding claws 4formed on the rear surface of a synthetic-resin-made wheel cover mainbody 5, and support members 3 arranged between adjacent holding claws 4,whereby a circular metal wire ring 2 used as a resilient ring is engagedwith foregoing holding claws 4 and support members 3, so that the radialmovement of the wire ring 2 is regulated by the support members 3.

The foregoing wheel cover 1 is composed of an approximately circularplate, i.e., main body 5, a plurality of holding claws 4 and supportmembers 3 are integrally formed at regular intervals on the rear surfaceof the circular plate 5, and an opening 7 for allowing air to flowtherethrough which is surrounded by a reinforcement wall 6 properlyformed at the portion between the holding claw 4a and support members 3,as well as at the portion between adjacent support members 3.

A plurality of holding claws 4 are, as shown in FIG. 4, formed atregular intervals on the rear surface of the wheel cover main body 5. Ashown in FIGS. 6-8, each holding claw 4 comprises a leg portion 4bprotruding from the rear surface of the wheel cover main body 5, and apair of head portions 4a formed at the tip of the leg portion 4b. Theradial outside surface of the head portion 4a is provided with anengaging portion 4d protruding in the form of a triangle in crosssection so as to engage with the concave portion 8b of the rim 8a ofwheel 8. A groove 4e is formed on the radial inside surface of the headportion 4a. A wire ring 2 is inserted in the groove 4e. The uppersurface of the groove 4e is provided with a first protrusion 4f, thelower surface of the groove 4e is provide with a second protrusion 4g. Athird protrusion 4h is formed at the portion corresponding to the secondprotrusion 4g and below a space 4c between the pair of head portions 4a.Therefore, the wire ring 2 in the groove 4e is engaged with the firstprotrusion 4f and second protrusion 4g, and at the same time, the wirering 2 between both head portions 4a and 4a is supported by the thirdprotrusion 4h, thereby positioning the wire ring 2. The first protrusion4f is formed to protrude radially inwardly more than the secondprotrusion 4g so as to prevent the wire ring 2 from being removed fromthe groove 4e in the upward direction in view of FIGS. 6 and 7.

Also, the foregoing leg portion 4b is so flexible that, when the wirering 2 is inserted into the groove 4e and subsequently when the wheelcover 1 is fitted to the wheel 8, the leg portion 4b is slightly,radially, and resiliently can bend so as to allow the wire ring 2 to besmoothly inserted slightly into the groove 4e, as well as the wheelcover 1 to be fitted to the wheel 8.

Moreover, a pair of support members 3 are formed between the adjacentholding claws 4 and 4. Each support member 3 is a plate member arrangedon the rear surface of the main body 5. The surface of the plate member3 is arranged in the radial direction. The plate member 3 has sufficientthickness and width so as not to be deformed even if a radial force isapplied, and not to be excessively bent even if a circumferential forceis applied. Also, the above-described support member 3 is connected tothe reinforcement wall 6 through a plate member 9 so as to be securelyprevented from being excessively bent circumferentially by the forceapplied circumferentially thereto.

The support member 3 described above is, as shown in FIG. 9, providedwith a pair of protrusions 3a and 3c formed at radially outside andinside portions of an upper surface confronting the wheel, respectively,and a groove 3b extending radially between the protrusions 3a and 3c,whereby the wire ring 2 is radially movably inserted into the groove 3blocated between the protrusions 3a and 3c. A height h1 of the firstprotrusion 3a with respect to the groove bottom surface, is formed to begreater than a height h2 of the second protrusion 3c with respect to thegroove bottom surface, and greater than a wire diameter of the wire ring2, thereby preventing the wire ring 2 in the groove 3b from radiallyoutwardly expanding. The second protrusion 3c is formed to be lower thanthe first protrusion 3a so that the wire ring 2 can be easily insertedinto the groove 3b. Namely, the wire ring 2 is inserted into the groove3b from the radially inside position over the second protrusion 3c tothe outside direction. The second protrusion 3c prevents the wire ring 2from being removed from the groove 3b when the wire ring 2 is insertedinto the groove 3b.

A groove end surface 3d of the first protrusion 3a is so formed to belocated on the circumference of the groove end surface 4i of the holdingclaw 4, or slightly radially outside the circumference of the groove endsurface 4i of the holding claw 4, wherein the wire ring 2 inserted inthe groove 4e of the holding claw 4 is so arranged to make a smallclearance 11 between the end surface 3d of some first protrusions 3a andend surface 4i of the holding claw 4. According to the constructiondescribed above, the wire ring 2 can exert a resilient force muchgreater on the holding claw 4 than on the support member 3 by the amountenhanced by means of the clearance 11, whereby the wheel cover 1 can besecurely held and pressed to contact with the wheel 8. A radial length Lof the groove 3b of the support member 3, is so formed to allow the wirering 2 to deform or move due to the bending of the holding claw 4 whenfitting the wheel cover 1 to the wheel 8, while the radial length Lshould be so formed not to allow the wire ring 2 to deform or move whenan excessive bending is generated on the holding claw 4. Also, a heightH2 of the bottom surface of the groove 4e from the reference surface ofthe wheel cover 1 is so designed to be lower than a height H1 of thebottom surface of the holding claw 4 from the reference surface of thewheel cover 1. Therefore, the wire ring 2 can move in the groove 3b ofthe support member 3 and the wrie ring 2 is prevented from falling tothe rear surface of the wheel cover main body 5 between the holdingclaws 4 and 4. In addition, under the condition wherein the wheel cover1 is fitted to the wheel 8 in a normal manner, a clearance 10 ismaintained between the outside end surface 3e of the support member 3and the rim 8a of the wheel 8, such that when an excessively eccentricload is applied to the wheel cover 1, the support member 3 is pressed tocontact with the wheel 8 so as to eliminate the clearance 10, therebypreventing an excessive bending of the wheel cover.

According to the construction described above, as shown in FIG. 4, thewire ring 2 is inserted into the grooves 4e of the holding claws 4 fromover the rear surface of the wheel cover main body 5 with the holdingclaws 4 bent radially outwardly, then the wire ring 2 is supported bythe grooves 3b of the support members 3 so as to be radially movable.When the wire ring 2 is inserted into the groove 4e of the holding claw4, the wire ring 2 is slightly bent, thus the resilient force exerted bythe bending movement acts on the holding claw 4, pressing slightly,radially, and outwardly the holding claw 4. Further, as shown in FIGS.10 and 11, when some holding claws 4 of the wheel cover 1 to which thewire ring 2 is fitted, are pressed to contact with the rim 8a of thewheel 8, those holding claws 4 and the wire ring 2 in the grooves 4e ofthe holding claws 4 are radially inwardly bent together. At this time,the portion other than the portion to which the bending force of thewire ring 2 is applied, is apt to extend radially outward. Subsequently,when some holding claws 4 are pressed into the wheel 8, the rest of theholding claws 4 other than the foregoing holding claw 4 are also apt toextending outwardly. However, they are prevented from extendingoutwardly by means of the first protrusion 3a of the groove 3b of thesupport member 3. Accordingly, some holding claws 4 and the rest of theholding claws are easily radially inwardly bent, thus the wheel cover 1is fitted to the wheel 8. The wheel cover 1 is fitted in the wheel 8together with the holding claw 4, with the wire ring 2 being bent,whereby the engaging portion 4d is engaged with the concave portion 8bof the rim 8a of the wheel 8 with the aid of the combined resilientforce exerted by the wire ring 2 and the holding claw itself, thus thewheel cover 1 is securely fitted to the wheel 8. The wheel cover 1 canbe removed from the wheel 8 by means of releasing the engagement of someholding claws 4 of the wheel cover 1 with respect to the rim 8a.

According to the embodiment described above, the support members 3 areformed, at the adjacent holding claws 4, on the rear surface of the mainbody 5, and the wire ring 2 is inserted into the grooves 4e of theholding claws 4 as well as into the grooves 3b of the foregoing supportmembers 3, whereby when the wheel cover 1 is fitted to the wheel, someholding claws 4 are bent toward the central portion together with thewire ring 2, the rest of the holding claws 4 are apt to extend radiallyoutwardly due to the resilient force exerted by the deformed wire ring2. However, since the first protrusions 3a of the grooves 3b of thesupport members 3 prevents the wire ring 2 from moving radiallyoutwardly, the rest of the holding claws 4 can be bent inwardly towardthe central portion with a relatively small force, thus in general,facilitating the wheel cover 1 to be fitted to the wheel 8. Also, evenif an external force is applied to the holding claw 4 so as toexcessively deform some holding claws 4, the radial movement of the wirering 2 is restricted by both protrusions 3a and 3c of the support member3, whereby the holding claw 4 is effectively prevented from beingexcessively deformed with the aid of the wire ring 2. When the wheelcover 1 is fitted to the wheel 18, the holding claws 4 are securelypressed to contact with the rim 8a of the wheel 8 by means of thecombined resilient force of the holding claw 4 itself and wire ring 2,so that the wheel cover 1 is securely held by the wheel 8.

Although the present invention has been fully described by way of anembodiment with reference to the accompanying drawings, it is to benoted here that various changes and modifications will be apparent tothose skilled in the art. For example, the configuration of the supportmember 3 may be integrally formed with the reinforcement wall 6, and theholding claws 4 may be formed in any desired number under the conditionthat the holding claws can perform the same function as that describedabove. In addition, a plate member 9 independent of the reinforcementwall 6, may radially reinforce the support member 3 with respect to thewheel cover main body 5. The reinforcement of the support member 3 isnot limited only to the configuration wherein a plate member 9 is formedat one side of the support member 3, but the support member 3 may bereinforced by two plate members formed at both sides of the supportmember 3.

Embodiment 2

The wheel cover according to Embodiment 1 has a following disadvantage.Referring to FIG. 12, which schematically shows a holding claw 4, whenforming holding claws 22 on the wheel cover main body 21a, a piece ofmetal mold A which is positioned inside the holding claws 4 and whichforms the inside surface of the holding craw having the foregoing groove4e is, as shown in FIG. 13, drawn after completion of injection moldingin such a manner that the metal mold 24 is moved upwardly so as toradially outwardly bend the holding claws.

At this time, a forcible drawing quantity d is restricted by length h ofthe holding claws 22. A guide quantity D of the tip portion of theholding claw 4 is also restricted. As a result, when mounting the wheelcover on a rim of a wheel, the tip portion of the holding claw cannot besufficiently guided with respect to the wheel. Therefore, the holdingclaws are not smoothly bent toward the central portion of the wheelcover main body, nor is the wheel cover smoothly fitted to the wheel.Furthermore, the wire ring may be removed during transportation of thewheel cover.

Accordingly, the object of Embodiment 2 is to solve the foregoingdisadvantage, i.e., to provide a wheel cover wherein the holding clawwill have a sufficient strength, the resilient ring such as wire ringcan be securely engaged to the holding claw, and moreover, the wheel iseasily fitted in the wheel cover.

FIGS. 14 through 20 shows Embodiment 2.

Referring to FIGS. 14-16, a wheel cover 101 according to Embodiment 2has generally, as shown in FIGS. 14 through 16, such a construction,wherein a plurality of holding claws 104 are provided on its rearsurface of the synthetic-resin-made wheel cover main body 105.Protrusions 104f are integrally formed on the circumferential side endsof each holding claw 104. Support members 103 are formed at both sidesof each holding claw 104. A circular metal wire ring 102 serving as aresilient member is engaged with two protrusions 104f of the holdingclaws 104 and the support members 103. Accordingly, a radial movement ofthe wire ring 102 is generally controlled by the support members 103.

The wheel cover 101 is generally comprises a wheel cover body, i.e., acircular plate, a multiplicity of holding claws 104 and support members103 being integrally circumferentially formed on its rear surface atregular intervals. A plurality of holding claws 104 are, as shown inFIG. 16, arranged at regular intervals on the rear surface of the wheelcover main body 105. Each holding claw 104 generally comprises a legportion 104b protruding from the rear surface of the wheel cover mainbody 105, and a head portion 104a having a groove 104e, formed at thetip portion of the leg portion 104b, into which the wire ring 102 isinserted. The radial outside surface of the head portion 104a isprovided with an engaging portion 104d protruding outwardly, which is tobe engaged with a concave portion 108b of a rim 108a of the wheel 108.The groove 104e is formed on the inside surface of the head portion104a, into which the wire ring 102 is inserted. A protrusion 104f isformed in the form of a triangle in cross-section at both ends of thehead portion 104a of the holding claw 104 along the circumferentialdirection. The radial inside tip portion of each protrusion 104fprotrudes radially inwardly over the inside surface of the groove 104eand the wire ring 102 fitted in the groove 104e. The lower surface ofeach protrusion 104f is a slant 104g, which is slanted radially fromoutside to inside so as to approach the wheel cover main body 105. Theangle formed by the radial inside surface of the head portion 104a ofthe holding claw and the slant 104g is less than 90 degrees. The wirering 102 inserted into the groove 104e is engaged with both protrusions104f. In this case, since the leg portion 104b of the holding claw 104is flexible, it can bend resiliently with respect to the rear surface ofthe wheel cover main body 105, so that the wire ring 102 can be insertedsmoothly and slightly into the groove 104e. Furthermore, when the wheelcover 101 is fitted into the wheel 108, the leg portion 104b allows eachholding claw 104 to bend easily in the radially inward direction,thereby facilitating the wheel cover 101 to be fitted smoothly into thewheel 108. The foregoing engaging portion 104d is provided with concaveportions 104h so as to prevent a sink which is liable to occur at thetime of injection-molding of the holding claws.

The above-described holding claw 104 is formed, as shown in FIGS. 18 and19, by means of the conventional molding method using the following somepieces of metal molds; a pair of radially-movable first metal molds 106for molding the slant 104g of each protrusion 104f, a second metal mold107 for molding the radially outside surface of the holding claw 104,and a third metal mold 109 for molding the groove 104e and the radiallyinside surface of the holding claw 104. Each of the foregoing firstmetal mold 106 is provided with a slant 106f slanting toward the centralportion of the wheel cover main body. The first metal mold 106 molds theprotrusion 104f with the aid of the second metal mold 107 and thirdmetal mold 109.

The first support member 103 is made of an approximately rectangularplate which is positioned on the rear surface of the wheel cover 104 insuch a way that the plate surface is positioned along the radialdirection and has enough width and thickness not to when subjected tothe radial force and to the circumferential force. At the top endsurface of each first support member 103 is formed a groove 103a whichcontrols the radial movement of the foregoing wire ring 102 so that thewire ring 102 does not excessively move in the radial direction inconjunction with the holding claw 104.

According to the construction described above, the wire ring 102 isinserted into the groove 104e and is engaged with both protrusions 104fwith the holding claw 104 outwardly bending in the radial direction. Thewire ring 102 is also inserted into and supported by a groove 103a ofthe first support member 103 as to be movable in the radial direction.When the wire ring 102 is inserted into the groove 104e of each holdingclaw 104, the wire ring 102 is slightly deformed. The resilient forcegenerated by this bending motion acts on the groove 104e of each holdingclaw 104, and slightly presses each holding claw 104 outwardly in theradial direction. Moreover, as shown in FIG. 20, when the holding claws104 of the wheel cover 1, wherein the wire ring 102 is fitted, arepressed into contact with the rim 108a of the wheel 108 and the holdingclaws are bent inwardly in the radial direction, the wire ring 102 inthe groove 104e of the holding claws 104 is bent together with theholding claws 104 inwardly in the radial direction. The engaging portion104d is engaged with the concave portion 108b of the rim 108a of thewheel 108 with the aid of the combined resilient force exerted by thewire ring 102 and the holding claws 104 themselves, thus the wheel cover101 is securely attached to the wheel 108. The wheel cover 101 can beremoved from the wheel 108 by means of releasing the engagement of someholding claws 104 with respect to the rim 108a.

In Embodiment 2 described above, as described above, both ends of theholding claw 104 are provided with protrusion 104f, and the insidesurface of the head portion 104a and the protrusions 104f arecircumferentially positioned at different locations so as to be moldedby the metal molds 106, 106, 107, and 109 which radially slide and theslant 104g of each protrusion 104f is formed so as to slant radiallyinwardly with respect to the wheel cover main body. Therefore, an angleformed by the inside surface of the head portion 104a of the holdingclaw and the slant 104g becomes less than 90 degrees, thus the wire ring102 is securely engaged with the protrusion 104f, without fearing thatthe wire ring is removed.

Also, the holding claws 104 are formed by means of moving the metalmolds 106, 106, 107, and 109 approximately along the rear surface of thewheel cover main body 105, whereby the leg portion 104b of each holdingclaw 104 can be easily formed so as to have a sufficient thickness, andthus the holding claw 104 can be provided with a sufficient strength.Further, protrusions 104f are formed on both side ends of the holdingclaw 104, and the wire ring 102 is inserted into the grooves 104e of theholding claws 104 as well as being engaged with the foregoingprotrusions 104f. After the wheel cover 101 is fitted to the wheel 108,the holding claws 104 can be securely pressed into contact with the rim108a of the wheel 108 with the aid of the resilient force generated bythe wire ring 102 and the resilience force of the holding claws 104themselves, thus the wheel cover 101 can be securely fitted to the wheel108.

Alternatively, the configuration of the holding claw 104 and protrusion104f may be of any desired configuration provided that the configurationcan have the same functions as those of the embodiment described above.Furthermore, the holding claw 104 may be so constructed as to have nogroove 104e on the foregoing holding claw 104, but instead, the wirering 102 may be simply abutted on the inside surface of the head portion104a, or the wire ring 102 may be arranged facing the inside surfacewith a small clearance therebetween.

Meanwhile, the configuration of the outside surface of the head portion104a of the holding claw 104 influences greatly on the degree of ease infitting the wheel cover 101 to the wheel. That is as clearly shown inFIGS. 21, 22A, 22B, and 22C, when the wheel cover 101 is fitted into thewheel 108, the outside surface 104h of the head portion 104a abuts onthe curved portion 108b of the rim 108a of the wheel 108, therebycausing a frictional resistance.

The outside surface 104h of the head portion 104a is normally comprisesa flat surface 104i, as shown by a dotted line in FIG. 21, followed by acurved surface 104j. However, the inventors of the present inventionhave found through various experiments that a gently curved surface 104kas shown by a solid line in FIG. 21 is better than the foregoing 104i.The following description deals with the configuration of the gentlycurved surface 104k.

FIGS. 22A through 22C show that the holding claw 104 slides on thecurved surface 108b of the wheel 108 wherein FIG. 22A shows the initialstage, FIG. 22B shows the intermediate stage, and FIG. 22C shows thefinal stage.

Supposing that with respect to the pressing force of the wheel coveragainst the wheel, N represents a perpendicular reaction force againstthe curved surface 108b of the holding claw 104, F represents acomponent of force (pressing force) of N in the pressing direction tothe wheel cover, S represents a perpendicular component of force(reaction force of the ring 102) of N in the pressing direction of thewheel cover, then the relationships of the forces can be stated in thefollowing equation shown below where θ represents an angle formed by thetangent line of the holding claw 104 and curved surface 108b withrespect to the perpendicular line in the pressing direction of the wheelcover. The relationship between S and F can be stated in the followingequation: ##EQU1##

As shown above, the pressing force F becomes maximum in the intermediatestage wherein the wheel cover is fitted into the wheel. To reduce thepressing force F, a value of 1/tan θ should be reduced, i.e., a value ofθ should be increased. The inventors of the present invention have foundthat the value of the pressing force F can be generally reduced by meansof manipulating the value θ, i.e., by means of making the value inaccordance with the solid line representing the curved surface 104k inFIG. 21. FIGS. 23A through 23D show the relationships between S, θ,1/tan θ, and F with respect to the bending degree of the holding claw.

In FIG. 23A, (P₁), (P₂), and (P₃) show the initial stage, intermediatestage, and the final stage corresponding to FIG. 22A, FIG. 22B, and FIG.22C, respectively. As shown in the figures, in the initial stage, thevalue θ of the flat surface 104i is larger than that of the curvedsurface 104k (FIG. 23B). Accordingly, regarding the curved surface 104k,1/tan θ is large, and F is also small (FIG. 23D). In the intermediatestage and final stage, however, a value θ of the curved surface 104k islarger than that of the flat surface 104i (FIG. 23B). Accordingly,regarding the curved surface 104k, 1/tan θ is small, and F is alsosmall. In other words, it is apparent that the pressing force F can begenerally made small when the outside surface 104h of the holding claw104 is so formed to be the curved surface 104k rather than to be theflat surface 104i.

Embodiment 3

Embodiment 3, as shown in FIGS. 26 through 32, is an improvement ofEmbodiment 2. Embodiment 2 has a disadvantage which will be described bymaking reference to FIGS. 24 and 25. It is to be noted that the wheelcover is generally formed by way of injection molding. As shown in FIGS.24 and 25, the engaging surface 104g of the protrusion 104f protrudinginwardly from the inside surface 104q of the head portion in the radialdirection, is formed by means of the outer metal mold 106 (FIG. 19),thereby permitting the engaging-surface-forming portion of the outermetal mold to locate radially inside the leg portion 104b of the holdingclaw 104. Therefore, in order to outwardly draw the outer metal mold104p upon completion of the molding process, the leg portion 104b musthave approximately the same width from its base portion 104m to aconnection portion 104m of the head portion. If the leg portion 21e is,as shown by a dotted line 104l in FIG. 25, so formed that its widthincreases from the connection portion 104n of the head portion towardthe base portion 104m, a triangle portion 104p behind the portion 10lremains when the metal mold is drawn outwardly, i.e., in a directionshown by an arrow X in FIG. 25. In this case, one idea is to drawinwardly the metal mold inwardly, but due to the restriction from theviewpoint of the design of the wheel cover, the metal mold cannot bedrawn inwardly. Thus, the leg portion 104b has to be of approximatelythe same width from the head portion to the leg portion, resulting in anexcessive stress at the base portion 104m.

Accordingly, the object of Embodiment 3 is to solve the above-describedproblems, i.e., to provide a wheel cover wherein the holding claw hassufficient strength and a leg portion is formed such that its widthincreases from the connection portion of the head portion toward thebase portion, resulting in sufficient strength.

Referring to FIGS. 26 through 31, a wheel cover 201 is generally soconstructed that, as shown in FIG. 27, a plurality of holding claws 204are formed on the rear surface of a wheel cover main body 205 which ismade of synthetic resin. The holding claw 204 comprises a head portion204a and a leg portion 204b. A slit 204c is formed in the leg portion204b. On the head portion 204a is formed a protrusion 204f which engagesand holds a wire ring 202 used as a reinforcement resilient member. Thewire ring 202, having approximately the same diameter as that of thecircumference wherein the holding claw 204 is arranged, is arranged onthe rear surface of the wheel cover main body 205 and positionedradially inside the holding claw 204 to be engaged and held by theprotrusion 204f. Therefore, when the wheel cover is removably fitted tothe wheel 208, each holding claw 204 is pressed to contact with the rim208a of the wheel 208 with the aid of the resilience of the wire ring202 and holding 204, thus the wheel cover 201 is mounted on the wheel208.

The wheel cover main body 205 is formed into approximately the shape ofa disc. A plurality of holding claws 204 and support members 203 areintegrally formed with the wheel cover main body 205 with regularintervals in the circumferential direction on the rear surface thereof.

The holding claw 204 comprises the leg portion 204b protruding from therear surface of the wheel cover main body 205, and the head portion 204ais formed at the tip of the leg portion 204b.

The leg portion 204b is so formed that its circumferential width Lgradually increases from the connection portion 204n connected with thehead portion toward the base portion 204m which connects the wheel covermain body 205, whereby the stress on the holding claw 204 can be madeuniform over the entire area of the leg portion 204b. Also, the wirering 202 is abutted on the inside surface 204e of the head portion so asto be engaged with the protrusion 204f. In this case, since the legportion 204b is flexible and accordingly slightly it resiliently bendswith respect to the rear surface of the wheel cover main body 205.Therefore, the leg portion 204b allows the wire ring 202 to abutsmoothly and slightly on the inside surface 204e of the head portion.Furthermore, when the wheel cover 201 is to be fitted into the wheel208, the leg portion 204b allows each holding claw 204 to bend easily inthe radial direction, thereby facilitating the wheel cover 201 to befitted smoothly into the wheel 208. In both circumferential end surfacesof the base portion 204m of the leg portion 204b, i.e., a side surfaces204j in the radial direction, a curved surface 204i is formed at theportion connecting each side surface 204j and the wheel cover main body205, thereby eliminating the stress concentration on the connectionportion. In the widthwise central portion of the leg portion 204b, theslit 204c extends from the base portion 204m to the head portion 204avia the connection portion 204n, thus penetrating the leg portion in theradial direction.

An engaging portion 204d protruding outwardly in the radial direction isformed on the outside surface in the radial direction of the headportion 204a. The engaging portion 204d engages with a rim 208a of aconcave portion 208b. The inside surface 204e is so arranged as to bepresent slightly inside the outer diameter of the wire ring 202, so thatthe wire ring 202 abuts on the inside surface 204e with the aid ofresilience of the wire ring thereof so as to press the engaging portion204d outwardly in the radial direction, i.e., to the engaging portion ispressed toward the rim 208a of the wheel 208. The top end portion of theslit 204c is located at a circumferential central portion of the headportion 204a of the holding claw 204. The protrusion 204f is located ata position adjacent to the top end of the slit 204c. Furthermore, thewire-ring-engaging surface 204g of the protusion 204f extends to the topend surface of the slit 204c. The protrusion 204f is so formed as tohave the cross-sectional shape of an approximate triangle protrudinginwardly in the radial direction. The inside tip portion in the radialdirection of the protrusion 204f protrudes inwardly over the wire ring202 which abuts the inside surface 204e. The wire-ring-engaging surface204g of the protrusion 204f facing the wheel cover main body 205 is soformed as to be a slant which inclines with respect to the wheel covermain body 205 from the radially outside portion to the inside portion,wherein the angle formed by the inside surface 204e of the head portion204a of the holding claw and the wire-ring-engaging surface 204g is lessthan 90 degrees, thereby preventing the wire ring 202 engaged with theprotrusion 204f from being removed from the protrusion 204f in theupward direction as shown in FIG. 29. In addition, concave portions 204hare formed on the head portion 204a between the engaging portions 204dso as to prevent a sink at the time of injectin-molding the holdingclaw.

The holding claw 204 is formed by means of the following processes. Asshown in FIG. 31, the holding claw 204 is injection-molded by the outermetal mold 207 which can move outwardly in the radial direction (to theleft in the drawing), and the inner metal mold 209 which can move in thedirection of the thickness of the wheel cover main body. The outer metalmold 207 molds the outside surface of each holding claw 204, i.e., theengaging portions 204d, the outside surface and side surface 204j havingthe curved surface 204i of the leg portion 204b, the concave portions204h, as well as the slit 204c of each holding claw 204 and engagingsurface 204g of the protrusion 204f, and so on. The inner metal mold 209molds the inside surface 204e in the radial direction of each holdingclaw 204, the protrusion 204f, and so on. The holding claw 204 is,therefore, molded by the combination of both metal molds 207 and 209 bymeans of the conventional injection-molding method.

Further, first support members 203 are integrally formed at constantintervals on the wheel cover main body 205 between the neighboringholding claws 204. A second support member 206 is formed at constantintervals on the inside surface of each holding claw 204. Each firstsupport member 203 is made of an approximately rectangular plate whichis positioned on the wheel cover in the circumferential direction insuch a way that the plate surface is positioned along the radialdirection and has enough width and thickness to prevent itself frombeing deformed when subjected to the radial force and from beingexcessively bent when subjected to the circumferential force. At the topend surface of each first support member 203 is formed a groove 203awhich controls the radial movement of the foregoing wire ring 202,thereby preventing the wire ring 202 from excessively moving in theradial direction in conjunction with the holding claw 204. Also, secondsupport member 206 includes a central wall 206a and a pair of side walls206b at both ends of a central wall 206a. The central wall 206a isarranged approximately in parallel with the inside surface 204e of eachholding claw 204 so as to face the slit 204c of each holding claw 204.When each holding claw 204 is bent excessively inwardly in the radialdirection, the inside surface 204e of each holding claw 204 contacts thecentral wall 206a of the second support member 206, thereby preventingthe holding claw 204 from being excessively bent.

According to the construction described above, as shown in FIG. 29, thewire ring 202 is allowed to directly abut on the inside surface 204e ofthe head portion 204b and to engage with the protrusion 204f. The wirering 202 is provided from the rear surface and over the protrusion 204f.The wire ring 202 is inserted into and supported by the groove 203a ofthe first support member 203 in such a manner as to be movable in theradial direction. When the wire ring 202 is abutted on the insidesurface 204e of each holding claw 204, the wire ring 202 is slightlydeformed; the resilient force generated by this bending motion acts onthe inside surface 204e of each holding claw 204, and slightly presseseach holding claw 204 outwardly in the radial direction. Moreover, asshown in FIG. 29, when the holding claws 204 of the wheel cover 201,wherein the wire ring 202 is fitted, are pressed to contact with the rim208a of the wheel 208 and the holding claws are inwardly bent in theradial direction, the wire ring 202 abutted on the inside surface 204eof the holding claw 204 is inwardly bent with the holding claws 204 inthe radial direction. Subsequently, the wheel cover 201 is graduallyfitted in the wheel 208, then the wire ring 202, together with eachholding claw 204 of the wheel cover 201, is fitted in the wheel 208,with the wire ring 202 being inwardly bent in the radial direction, thusthe wheel cover 201 is completely fitted in the wheel 208, whereby theclaw body 204d is engaged with the concave portion 208b of the rim 208aof the wheel 208 with the aid of the combined resilient force exerted bythe wire ring 202 and the holding claw itself, thus the wheel cover 201is securely held by the wheel 208. The wheel cover 201 can be removedfrom the wheel 208 by means of releasing the engagement of some holdingclaws 204 of the wheel cover 201 with respect to the rim 208a.

According to Embodiment 3 described above, since the wheel cover is soconstructed that the slit 204c is formed in the leg portion 204b of eachholding claw, wherein the outer metal mold 207 is inserted in the radialdirection through the slit 204c so that the wire-ring-engagement surface204g is formed such that the top end surface of the slit 204c becomes apart of the wire-ring-engagement surface, consequently, even if theinner metal mold 209 is so designed as to be drafted in the direction ofthe thickness of the wheel cover main body 205, the angle formed by thewire-ring-engaging surface 204g and the inside surface 204e of the headportion can be made to less than 90 degrees. The leg portion 204b can beformed in such a manner that its width increases from the connectionportion 204n toward the base portion 4m, and the leg portion 204b can beprovided with a sufficient strength, whereby the stress acting on theholding claw 204 can be effectively prevented from increasingexcessively. Also, the protrusion 204f having engaging surface 204g forengaging the wire ring 202 at both ends of the head portion 204a, iseliminated and the protrusion 204f is formed at the intermediate portionof both ends, therefore, the leg portion 204b can be so formed as tohave the desired width without being restricted by the protrusion 204f.The wire ring 202 can be securely engaged with the engaging surface204g. Further, the connection portion of each side surface 204j andwheel cover main body 205 can be formed in the form of the curvedsurface 204i in the base portion 204m of the leg portion 204b, wherebythe stress concentration on the foregoing connection portion can beeffectively prevented.

The configuration of the foregoing second support member 6 is notlimited only to a U-shaped wall, but any other configuration, forexample, a support member 206' which is formed from a parallelepipedbody, may be utilized as shown in FIG. 32.

Embodiment 4

The Embodiment 1 has such a disadvantage that, when the wheel cover isto be fixed to the rim of the wheel and when the head portion of eachholding claw contacts the wheel rim, the head portion may beaccidentally guided along the rim toward the center of the wheel, thatmay be reversely guided in the outward direction, causing the foregoinghead portion to bend in the outward direction of the wheel cover mainbody and not to engage the concave portion of the rim, thus making itdifficult to insert the wheel cover into the wheel, and in an extremecase, with the result that the holding claw suffers plastic deformation,cannot be forcibly pressed against the rim, which makes it difficult toattach and hold the wheel cover onto the wheel. The inventors of thepresent invention have analyzed the cause of this problem as describedhereinbelow according to FIGS. 33 and 34. It is to be noted that FIGS.33 and 34 shows substantially the same holding claw as that ofEmbodiment 1.

When each holding claw 4 is, as shown in FIG. 33(a), contacted by therim 8a of the wheel 8, a reaction force P from the wheel acts on theholding craw 4 at a contact point. This reaction force P can be dividedinto a component force Ps acting along the axial direction of the legportion 4b of the holding claw 4 and a component force Pr acting alongthe direction intersecting orthogonally the above-mentioned direction,i.e., the radial direction of the wheel cover main body. A momentdiagram in terms of each component force is shown in FIGS. 33(b) and(c), where the length of the holding claw 304 extending from the rearsurface of the wheel cover main body is expressed as L, and the distancefrom the contact point between the holding claw 4 and the rim 8a to theinside surface of the leg portion 4a for the holding claw 4 is indicatedas l. As illustrated in FIG. 33(d), with the sum of the momentsresulting from the above-described component forces, the moment Ps·l,which has a tendency to bend the holding claw 4 is the outwarddirection, acts on both the head portion 4a and a portion, close to thehead portion, of the leg portion 4b, while the moment Pr·L, which has atendency to bend the holding claw 4 in the inward direction, acts at aportion, on the wheel cover main body, of the leg portion 4b of theholding claw 4. It is conceivable from FIG. 33 that the maximum momentacts on the head portion of the holding claw 4. However, the headportion 4a is free from deformation due to the high geometrical momentof inertia acting therein. Rather, at a constricted portion of theholding claw 4, i.e., at a portion, close to the head portion, of theleg portion 4b, the stress is maximum and the deformation tends tooccur. In actuality, the compressed force resulting from the axialcomponent force Ps acts on the holding claw 4 in addition to theforegoing moment such that the holding claw 4 is more liable to besubjected to, as it were, neck-breakage.

Referring to FIG. 34, to permit the rim 8a of the wheel 8 to securelyfacilitate guiding along a guide portion 4l on the top surface of thehead portion 4a for the holding claw 4, it is necessary to enlarge asmuch as possible a radial dimension l1 of a guide portion 4l on the topsurface of the head for the holding claw 4. At the same time, since aslope on the internal surface of the head portion for the holding claw 4is, as it were, an undercut against the mold draw direction (in thedirection of an arrow A as indicated in FIG. 34), it is necessary tominimize a radial dimension l2 of an undercut portion so as to reduceforced draw amount with the result that the dimension between theinternal surface of the leg portion 4b and the external surface of thehead portion becomes large and is expressed as l₃ =l₁ -l₂. Consequently,when the head portion 4a of the holding claw 4 is to be bent in theradially inward direction, the dimension l between a contact point, whenthe rim 8a of the wheel 8 contacts the head portion 4a of the holdingclaw 4, and the internal surface of the leg portion of the holding claw4 becomes large, attaining the size of the foregoing dimension l₃.Consequently, the moment Ps·l increases, causing the head portion of theholding claw 4 to bend in the radially outward direction, hamperingsmooth sliding of the head portion 4a along rim 8a toward the center ofthe wheel, thereby making it difficult to bend the holding claw 4 alongthe rim in the radially inward direction, which conceivably makes itdifficult to fit the wheel cover into the wheel.

The inventors of the present invention have revealed that, in order toprevent the head portion of the foregoing holding claw from bending inthe radially outward direction of the wheel cover main body, theexternal surface of a portion, close to the head portion, of the legportion, at which the foregoing maximum stress occurs, should be formedby a thick wall so as to increase the geometrical moment of inertia atsaid portion, thereby preventing extreme lowering of the geometricalmoment of inertia at said portion, thus effectively preventing the headportion from bending in the outward direction.

In view of the foregoing problem, the object of this Embodiment 4 is toprovide a wheel cover which allows the holding claws to securely bend inthe radially inward direction and which can be easily attached to thewheel.

Referring to FIG. 35-FIG. 39, the Embodiment 4 is described below;

A wheel cover 301 according to the present embodiment, as illustrated inFIG. 35 and FIG. 36, is so constructed that a plurality of holding claws304 are integrally formed on the rear surface of an almost circularwheel cover main body 305 made of synthetic resin, and a circularmetallic wire ring 302 for reinforcement as a resilient ring is held byeach said holding claw 304, wherein, when the wheel cover 301 isremovably inserted into a wheel 308, a head portion 304a of each saidholding claw 304 is forcibly pressed against a rim 308a of the wheel 308by means of the resilience of both the foregoing wire ring 302 and eachsaid holding claw 304.

Each foregoing holding claw 304 mainly comprises a leg portion 304bprotruding from the rear surface of the wheel cover main cover 305 and ahead portion 304a formed at the top of said leg portion 304b. There isprovided an engaging portion 304d evaginated on the radial outside ofthe head portion 304a and fitted into a concave portion 308b of the rim308a of the wheel 308. There is provided a protrusion 304f in the shapeof triangle in section which protrudes from each of both ends along thecircumferential direction of the foregoing head portion 304a. Eachprotrusion 304f protrudes in the radial direction more inwardly than aninternal surface 304e of the foregoing head 304a and which abuts on theinternal surface 304e so that the wire ring 302 is securely held by eachprotrusion 304f and is prevented from being removed toward the lowerside in view of FIG. 36. The bottom surface of each protrusion 304f isshapely formed into a slope 304g in such a way that the bottom surfaceapproaches the wheel cover main body 305 as it moves in the directionfrom the outside radius to the inside radius, and an angle formedbetween the radially inside surface 304e and the foregoing slope 304g isless than 90 degrees. Further, the foregoing leg portion 304b isflexible so that, the wire ring can be fitted into the holding claws 304and be engaged with the protrusions 304f to be held. Subsequently, thewheel cover 301 can be easily attached to the wheel 308 since the legportion 304b can be bent inwardly.

A thick reinforcement portion 304c is integrally formed, projecting froma portion, close to the head portion, of this leg portion, i.e., theexternal surface of a portion where the foregoing moment Ps·l acting onthe holding claw 304 becomes high due to the reaction force P generatedfrom the rim 308a when the head portion 304a bends by abutting on therim 308a of the wheel 308. The side configuration of said reinforcementportion 304c is formed in a triangular shape in such a way that the sideof said reinforcement portion 304c becomes thin as it moves in thedirection from the vicinity of the head portion toward the wheel covermain body. This reinforcement portion 304c effectively prevents extremelowering of the geometrical moment of inertia at a portion where theforegoing moment Ps·l of the leg portion 304b becomes high. Thisreinforcement portion 304c, as illustrated in FIG. 37, may be formedinto a shape with two convex portions 309 and 309 at the foregoingcorresponding area of the leg portion 304b, one convex portion 310 asshown in FIG. 38, or a convex portion 311 protruding from the entiresaid corresponding area as shown in FIG. 39. That is, the configurationof the reinforcement portion 304c may be arbitrarily arranged, providedthat the above-described measures are attainable. The foregoingreinforcement portion 304c is not necessary a portion, in the vicinityof the wheel cover main body, of the leg portion 304b since the momentis low at a portion close to the wheel cover main body, thus permittinga low geometrical moment of inertia. Concave portions 304h are formed inthe foregoing engaging portion 304d so as to prevent sink caused at thetime of molding the holding claw.

In FIG. 35, numeral 303 shows a support member. The foregoing circularmetallic wire ring 302 is received by a groove or recess on the top endsurface thereof so that the radial movement of the wire ring 302 iscontrolled.

According to this construction, as illustrated in FIG. 36, the wire ring302 is crossed over the projections 304f of each holding claw 304, witheach holding claw 304 being bent, and the wire ring 302, held by bothprojections 304f of each holding claw 304, is contacted by the internalsurface 304e of the head portion 304a. At the same time, the wire ring302 is inserted into the groove of each support member 303, therebybeing allowed to freely make a radial movement within a fixed range whensupported thereon. The wire ring 302, when remaining contacted by theinternal surface 304e of each holding claw 304, slightly bends, causingthe resilience corresponding to the magnitude of the bending to beapplied to each holding claw 304; thus each holding claw 304 is slightlypushed onto the outside radius. When the wheel cover 301 is to beattached to the wheel 308, the holding claws 304, which are part of theforegoing wheel cover 301, begin to be successively contacted, by therim 308b of the wheel 308. When the head portion 304a of each holdingclaws 304 abuts on the rim 308a of the wheel 308, the reinforcementportion 304c controls the radially outward bending of the head portion304a of the holding claw 304, causing the head portion 304a to bend inthe radially inward direction, sliding along the rim 308a and engagingthe concave portion 308b of the rim 308a. Each holding claw 304 isforcibly pressed against 308, thus the wheel cover 301 together with theforegoing holding claw 304 is finally mounted to the wheel 308 with thewire ring 302 being bent. Under this condition, a force, i.e., the sumof the resiliences of the foregoing holding claw itself and the wirering 302, acts on each holding claw 304, whereby the engaging portion304d of the head portion 304a for each holding claw 304 engages theconcave portion 308b of the rim 308a for the wheel 308 so that the wheelcover 301 is securely fixed to the wheel 308. When the wheel cover 301is to be removed from the wheel 308, the forcible pressing of theholding claw 304, a part of the wheel cover 301, against the rim 308afor the wheel 308 is released, and the wheel cover 301 can be removed ina manner similar to that of a conventional wheel cover.

According to the above-described embodiment, when the head portion 304aof each holding claw 304 abuts on the rim 308a and is thus subjected tothe reaction force therefrom, the head portion 304a has a tendency tobend onto the outside radius of the wheel cover main body 305. However,the reinforcement portion 304c controls the outward bending of this headportion 304a since the reinforcing portion 304c is formed on a portion,close to the head portion, of the leg portion 304b. Thus, the headportion 304a bends inwardly, guidedly slides along the rim, and engagesthe inside of the concave portion 308b. Consequently, at a portion ofthe holding claw 304 where the stress is high, i.e., a portion where themoment shown in the moment diagram is high, the geometrical moment ofinertia increases with the aid of the reinforcement portion 304c.Furthermore, at a portion, close to the wheel cover main body, of theholding claw 304 where the moment is low, the geometrical moment ofinertia decreases due to the absence of the reinforcement portion 304c,whereby the internal stress is uniformly spread throughout the entireleg portion, thus effectively preventing local deformation or bending,and consequently, the wheel cover 301 can be easily attached to thewheel 308. That is, a guiding portion 304i resting against the rim 308acan be securely maintained in each holding claw 304 with the result thatthe head portion 304a has effective guiding ability, thereby allowingeasy attachment of the wheel cover 301 to the wheel 308. Further, at thetime of molding each holding claw 304, the amount of undercut againstthe mold draw direction of the internal surface 304e is possible tominimize, which in turn allows the mold draw by the forced draw, hencelow cost of the mold.

What is claimed is:
 1. A wheel cover for motor vehicles comprising:awheel cover main body having a plurality of holding clawscircumferentially formed on a rear surface thereof; said holding clawsbeing provided with an engaging portion formed on an inner radialsurface thereof; a resilient reinforcement ring having approximately thesame diameter as a diameter defined by said holding claws; saidresilient reinforcement ring being inserted into said engaging portion,whereby said holding claws, when said wheel cover is removably fitted toa wheel, are pressed to contact with a rim of the wheel by an inherentresilience of said holding claws and said resilient reinforcement ring;and a plurality of pairs of support members radially movably supportingsaid resilient ring, said support members being formed on the rearsurface of said wheel cover main body between adjacent ones of saidplurality of holding claws and respectively having a pair of radiallyspaced inner and outer protrusions which enable and regulate the radialmovement of said resilient ring and are formed on a surface of saidsupporting member confronting said wheel whereby a radially innersurface portion of said outer protrusion is positioned radially outsideof said engaging member of each said plurality of holding claws.
 2. Awheel cover as claimed in claim 1, wherein the head portion of each ofsaid holding claws have a pair of protrusions formed at opposingcircumferential ends of each claw which extend inwardly in the radialdirection over a radial inside surface of said head portion, saidprotrusions engaging and holding said resilient ring.
 3. A wheel coveras claimed in claim 1, wherein each of said plurality of holding clawsincludes a leg portion and a head portion, the leg portion of each saidholding claw having a slit which radially penetrates said leg portionfrom a base portion connecting said wheel cover main body to said headportion, a projection being formed on the radial inside surface of thehead portion of said slit, protruding substantially inwardly in theradial direction with respect to the radial inside surface of said headportion and having a wire-ring engaging surface which engages and holdssaid resilient reinforcement ring, and said leg portion having such adimension that its width gradually increases from a head connectionportion to said base portion.
 4. A wheel cover as claimed in claim 3,wherein said wire-ring engaging surface and radial inside surface ofsaid head portion make an angle of less than 90 degrees.
 5. A wheelcover as claimed in claim 1, wherein said wheel cover further includes aplurality of secondary support members which are formed at constantintervals and at the inner periphery of each of said plurality ofholding claws on said main body, whereby each of said secondary supportmembers abut on and supports each of said holding claws in response to aradially inward inclination of said holding claws.
 6. A wheel cover asclaimed in claim 5, wherein each of said secondary support membersincludes a central wall confronting an inside surface of said holdingclaw, and side walls which are provided on each end of said central walland are positioned along the radial direction of said main body.
 7. Awheel cover as claimed in claim 1, wherein said holding claw includes aleg portion and a head portion, the leg portion having a thickreinforcement portion integrally formed on the radially outside surfaceof said leg portion in the vicinity of said head portion.